Lycium Barbarum Polysaccharide-Iron (III) Chelate as Peroxidase Mimics for Total Antioxidant Capacity Assay of Fruit and Vegetable Food

A review of Lycium barbarum polysaccharides: Extraction, purification, structural-property relationships, and bioactive molecular mechanisms

Lycium barbarum L. is of great significance medicinal and edible plant, which is native to N. & Central China. The extensive health benefits of L. barbarum have earned it great respect in traditional medicine for centuries. Lycium barbarum polysaccharides (LBPs) being recognized as one of the most crucial bioactive compounds found within this plant, with it exhibit a diverse range of pharmacological activities and nutritional functions, thereby generating substantial market demand and broad application prospects. To gain a more comprehensive understanding of LBPs, the review discussed the extraction, purification and structural-property relationships of these compounds. In addition, this review provides a comprehensive summary of the potential mechanisms underlying various biological activities attributed to LBPs, including immune modulation, antioxidant effects, neuroprotection, hepatoprotection, and antitumor properties. The application status and the future research directions of LBPs were subsequently presented. This review will establish a robust foundation and serve as an invaluable resource for future research and advancements in the field of LBPs.

Preparation and Performance Evaluation of Polysaccharide-Iron Complex of Eucommia ulmoides

An innovative iron supplement crucial for treating iron-deficiency anemia was developed in this study. Polysaccharide was extracted from Eucommia ulmoides leaves using a microwave-assisted hot water method, and subsequently, the polysaccharide-iron complex was synthesized through co-thermal synthesis with FeCl3. The physicochemical properties, structure, and thermal stability of the complex were analyzed using FE-SEM, SEC-MALLS, FT-IR, XRD, and DSC techniques. Furthermore, the antioxidant activity of the polysaccharide-iron complex was evaluated through an experiment in vitro. The results revealed that the polysaccharide-iron complex had an iron content of 6.1% and an average particle size of 860.4 nm. The microstructure analysis indicated that the polysaccharide-iron complex possessed a flaky morphology with smooth and compact surfaces. Moreover, the formation of the Fe3+ complex did not alter the structural framework of the polysaccharide; instead, it enhanced the polysaccharide's thermal stability. Compared to traditional iron supplements, the E. ulmoides-derived polysaccharide-iron complex demonstrated significant antioxidant activity. Therefore, this novel compound exhibits significant potential as a viable iron supplement.

Structural characterization and biological activities of polysaccharide iron complex synthesized by plant polysaccharides: A review

Iron deficiency anemia can lead to a variety of functional disorders, which is one of the highest incidence of nutrient deficiency diseases. The direct addition of iron to food will not only brings difficulties to the production of products, but also brings damages to human body. In recent years, international studies have shown that polysaccharide iron complex (PIC) not only has a variety of pharmacological activities of polysaccharide itself, but also has the function of supplementing iron, so it is a good iron supplement. With the advantages of good solubility, high iron content, low gastrointestinal irritation and high bioavailability, PIC is an effective iron supplement for iron deficiency anemia and has attracted more and more attention. In this paper, the different preparation methods, structural characterization, biological activities and clinical applications of PIC synthesized by natural polysaccharides from plant were reviewed, in order to provide theoretical basis for the development and application of PIC.

Construction of Pd Single Site Anchored on Nitrogen-Doped Porous Carbon and Its Application for Total Antioxidant Level Detection

Natural enzymes have excellent catalytic activity. However, due to their unstable nature and high cost, current research has turned to the synthesis and development of enzyme-like nanomaterials and single-atomic nanozymes. In this study, a single-atomic palladium-loaded nitrogen-doped porous carbon catalyst (SA-Pd/NPC) was prepared and used as a mimetic peroxidase to catalyze the substrates oxidation. The catalytic capability of the SA-Pd/NPC was tested by the TMB-H₂O₂ system, and it expressed a superior catalytic capability owing to the plentiful catalytic centers of the single-atom Pd, its high porosity, the large specific surface area, and the strong electron transfer capability of the NPC. For the color reaction of TMB, thiol antioxidants (e.g., glutathione, GSH) and non-thiol antioxidants (e.g., ascorbic acid, AA) are suitable for different inhibition mechanisms. GSH and AA are typical substances of these two main antioxidant types, respectively. Here, we demonstrate that this prepared catalyst could be used to simultaneously determine a variety of major known physiologically relevant thiol-containing and thiol-free antioxidants, accompanied by a blue color gradient change with UV-Vis spectra at 652 nm through the SA-Pd/NPC-catalyzed TMB-H₂O₂ system. Linear responses to GSH and AA could be obtained in the concentration ranges of 0.01-0.10 mM and 1-13 μM (both R² values were greater than 0.970), respectively, while the limits of detection were 3 μM and 0.3 μM, respectively. The ability of the nanozyme to detect overall antioxidant levels (TAL) was also confirmed in subsequent tests on artificial saliva and biological samples.

Physiological and Biochemical Variations in Celery by Imidacloprid and Fenpyroximate

Pesticides are one of the abiotic stresses that have had an impact on the quality of agricultural products, especially in China. This study was the first to explore the soluble protein (SP) accumulation, peroxidase (POD) activity, and superoxide dismutase (SOD) activity variations in the stem and leaf of celery plants in the field after 2 h, 1, 3, 5, 8, 10, 14, 21, 28-day of spraying imidacloprid (IMI) and fenpyroximate (FEN) at various doses. The findings demonstrated that there was no notable difference in ultimate residues between 1 F and 10 F, and even with the 10 F treatment, the residues were not a concern. The SP accumulation alterations were mainly provoked by residues, which dramatically boosted in stem and eventually declined in leaf. The POD activity in celery was a dynamic process with a marked shift (enhanced and declined) when compared with non-pesticide treatment after 28 days. The field trial exhibited that the SOD was principally positioned in leaf whether pesticides were applied or not, which might be due to the distinctive structure of the celery leaf compared with the stem. No obvious linear relation between application dose and SOD activity was observed.